Abstract

In recent years, a phenomenon was appeared that the whole needles of Pinus tabulaeformis Carr. turned red from the top to the bottom in a large area of Baotou city. In order to analyze the effects of nutrients on this phenomenon, comparative analysis of this article by red needles and normal needles in Baotou of Pinus tabulaeformis Carr. of the physical and chemical properties of soil, needle nutrient content, correlation between needle nutrient and soil nutrients and fertilization effects of different approaches, and combined with differences of significance test, correlation analysis and factor analysis, reached the following main conclusions:(1) Difference of soil physical and chemical properties is one of the reddening needles Pinus tabulaeformis Carr. causative factor, especially high soil pH value, low alkali-hydrolyzable Nitrogen, low radily available Potassium, low available Manganese significantly (P<0.05) induced by the Pine needles reddening. Compared to the.reddening needles and normal needles, high soil pH values of0.27, low alkali-hydrolyzable Nitrogen of8.62mg·kg-1, low radily available Potassium of12.06mg·kg-1, low available Manganese of2.89mg·kg-1(2) Difference of needle nutrient content is also the reddening needles Pinus tabulaeformis Carr. causative factor, especially low nitrogen content, high Calcium content, high Iron content, low Copper content, significantly (P<0.05) induced by the Pine needles reddening. Compared to the reddening needles and normal needles, the nitrogen content of a age and the second needles respectively lower0.36%and0.28%. the Calcium content respectively higher0.21%and0.35%, the Iron content respectively higher122mg·kg-1and68mg·kg-1, the Copper content respectively lower6.57mg·kg-1and7.67mg·kg-1(3) Nutrient cycle disproportion is another reddening needles Pinus tabulaeformis Carr. causative factor. Which Ca-ACa. Fe-AFe, Mn-AMn correlation is the opposite of significant difference (P<0.05). Nutrient cycling of Calcium, Iron, and Manganese disorder significantly induced by reddening needles Pinus tabulaeformis Carr..(4) Reddening needles foliar fertilization (N、P、K、Mn、Cu、Zn) and the roots of Nitrogenous fertilizers, a year after fertilization can significantly (P<0.05) reduce reddening degree of needles, compared with contrast respectively reduced19.73%and20.17%.